The objective of this project is the development of a small, pre-packaged disposable assay kit for the determination of carboxyhemoglobin (COHb) levels in blood of patients suspected of carbon monoxide intoxication (COI). Carbon Monoxide, one of the most comon and deadly gaseous pollutants associated with our way of life, is responsible for a large number of fatalities and incapacitating morbidities yearly in the United States Patient Treatment for COI is usually based on the level of COHb. In many centers levels of 15 or 20% COHb or above are considered (in combination with the clinical picture) to indicate Hyperbaric Oxygen Therapy (HOT). Unfortunately, only the larger medical centers can afford the equipment necessary to rapidly determine COHb levels and even in these larger centers samples from accidents occurring late at night or in the early morning often do not get analyzed for several hours. The situation in surburban and rural areas can be even worse. For this reason, a rapid means to measure blood COHb levels in patients suspected of sustaining COI would provide immediately information critically needed for the patients immediate treatment and medical prognosis. Such a device or system should require no training and be operable by individuals who first respond to medical emergencies such as aid car operators, firemen, ER nurses etc. Development of such a device will proceed along the established principles of analysis developed by Scholander & colleagues for measuring blood gases including CO in small samples of blood. Several mechanical approaches will be explored to develop the optimal system which should have the characteristics of simple operation, reliability, maximum accuracy, maximum shelf-life and ease of manufacturing. This Phase I study will explore all those alternatives necessary to develop a compact portable device which would be so simple to operate that a measurement would simply involve injecting or withdrawing a blood sample of 1.0 to 5.0cc. into the device and reading a pressure difference which would be proportional on a pre-existing scale to %COHb in the original blood sample. Since the basic analytical chemistry for such reactions have long been known it seems certain that such a simple "shelf-pack" can be developed rather quickly. Such devices would then become another part of the first-responding paramedics equipment and would have a commercial market in every medical and paramedical facility in the country. This would lead to much more effective screening of COI patients and measureably improve the fatality and morbidity statistics.